Blonde Bassman build suggestions...

[dehughes]

Hey all,

So, I'd like to get things together for a Blonde Bassman build...looking to be a 6G6-B head type creation. I have a nice chassis with two 9 pin and two octal sockets, so I'm good for the tube compliment, being as I'd like to build something off of the Normal Channel.

I'm going to put in a switch for high/low filtering in the power section, and probably a choke/resistor switch as well. Beyond that, I don't have any crazy ideas...but I figure there has to be something cool I could do with it....so, I'm asking you all. Any ideas?

[Firestorm]

Do you want to keep a "Bass" channel? The Bass channel in the 6G6 is a weird one, but if you look at the circuit it has the potential to be a screaming lead channel.

[dehughes]

Do you want to keep a "Bass" channel? The Bass channel in the 6G6 is a weird one, but if you look at the circuit it has the potential to be a screaming lead channel.

Dunno....thought about that, but I only have 5 holes for pots on the front, and only two 9-pin holes for tubes. Though I could always punch more holes for tubes, I'm kinda limited for pots...

[fakeox]

Weber has the special tapped tonepot you need..

[BTF]

I have an old AA864 I converted years ago to a 6G6-B and loved it (please no catcalls as I did the re-work long before the current craze over 864s!).

If you're only going to use one channel, here's a few suggestions though they may stress your pot count:

1) A feedback pot (install a 10K resistor in the negative feedback line and place a 100K pot in series with the resistor and speaker out). You can "tune" the feedback and looseness of the power section by adding or subtracting negative feedback. You could mount this pot on the back of the amp.

2)A "slope" pot for the tone stack which will vary the tone stack's response. Replace the resistor in the tone stack with a 10K, break the connection between the resistor and the junction of the Bass and Mid capacitors and put a 100K pot as a variable resistor between them (note that the amp will get louder as the pot's resistance is decreased, so wire the pot accordingly). Also note that this pot will carry a high voltage internally, so use a high quality pot. For this reason you may also want to disregard this mod, but it IS a possibility. I used it in a preamp I built a few years back and it was an interesting item to experiment with.

3)A "fat/thin" switch on the phase inverter choke capacitor. You can use the switch to add a parallel .047uF/400V cap to the 500pF input choke capacitor used in the 6G6-B. This will give the phase inverter the same value as the 6G6-A and is a very nice, full sound. There may be a bit of blocking distortion at higher volumes, but that can be cured by the selector switch.

Hope these might give you some food for thought. Regards, BTF.

[dehughes]

Fakeox: Not sure what you're referencing...lemme know...

BTF: Cool ideas! I was going to do something with the feedback resistor as well..but I dig the "slope pot" idea big time. I was thinking PEC or Clarostat RV-4 pots for this one, so I'm sure they'll be solid enough to handle what I throw at them.

What about a midrange pot? Is that "useful" with the 6G6-B circuit, or is that a waste of a pot? I ask, because I put a pot in place of the "mid resistor" on an AC30 creation...but end up leaving it mostly at the 10k-ish setting most of the time anyway. The fat thin idea is great as well...

[Structo]

The tapped pot is used on some Fender circuits I believe.
It's a 350K pot with a 70K tap.

[img:446:310]https://taweber.powweb.com/store/350k.jpg[/img]

https://taweber.powweb.com/store/potsord.htm

[fakeox]

yup.

[dehughes]

Right...I get all that, but I don't see where that pot goes in a Bassman schematic... I must be missing it...

AH! On the treble pot. Interesting. What's the deal with that? Should I keep it, or just use the standard tonestack setup? That is, how big of a deal is that odd treble pot...?

[gldtp99]

Last night a friend came over and demo'd many amps to see what basic circuit he wants for the 2 x 10 combo i'll be building for him----he played many different Tweed, BF, Marshall, Hiwatt, etc. amps---- some real "factory" amps but most were my builds---he plays Country, Blues, and Blues/Rock with a Strat and sometimes with his '60 Jazzmaster.
Power levels ranged from 10 to 85 watts and all were played through the 2 x 10 combo cab loaded with Celestion G10 Vintage speakers----sometimes a 2 x12 closed back cab was added to give a 2 x 10 and 2 x 12 "halfstack".
After many hrs of playing/comparing the "winner" was a 6G6-B based head i built--- this is sort of a hybrid of a modded 6G6-B and a Plexi-----6G6-B normal channel based preamp into Mullard xf4 EL34's and using Plexi-style iron.
I used the 350k/70k treble pot (same as all the other Brownface-type builds i've done) and i added a Mid pot--- it is a useful addition, IMO.
This 6G6-B based preamp will be the basis for the clean channel for the 2 x 10 combo i'll be building for him. Planning on using 6L6GC's in this one and i'm deciding on iron right now.
The 50 watt 6G6-B/Plexi head can be heard here: http://www.soundclick.com/bands/default ... dID=741589
Click on "Mule BP50"----another friend did the backing track and played a Strat for this clip....................gldtp99

[dehughes]

Cool. So then, the treble pot is an essential part of the 6G6-B, huh?

What value mid pot? 10k? 25k?

[paulster]

Do you want to keep a "Bass" channel? The Bass channel in the 6G6 is a weird one, but if you look at the circuit it has the potential to be a screaming lead channel.

Yeah, I'd keep the bass channel.

Take a listen to anything from Social Distortion and Mike's tones are all Bassmans, either blondes or blackfaces, but using the bass channel that's been modified slightly (more for voicing rather than gain).

[rawnster]

Hey David, another idea would be to talk with TV the Wired Turtle and tell him what you're wanting to build. He's a 6G6-B nut; His current amp, I believe is a real 1963 6G6-B that was slightly modified by Brian Gerhart.

[gldtp99]

Cool. So then, the treble pot is an essential part of the 6G6-B, huh?

What value mid pot? 10k? 25k?

If trying for Brownface 6G6-B clean channel tone then the 350k/70k treble pot is needed-----i've also built Brownface Tremolux and Bandmaster circuits using this pot---- but if building the 6G6-B Bass channel this 350k/70k pot isn't needed----it just depends on what you want to build.
For the 6G6-B/Plexi head i was interested in seeing what kind of tone quality i could get out of the single preamp 12ax7 + PI (6G6-B clean channel)------ i already knew i could get impressive tone out of a 5F6-A/early Marshall-type preamp configuration, with two preamp tubes before the PI-----maybe i'll look into building the 6G6-B bass channel in a later build.
I used a 10K Mid pot.........................gldtp99

[dehughes]

Do you want to keep a "Bass" channel? The Bass channel in the 6G6 is a weird one, but if you look at the circuit it has the potential to be a screaming lead channel.

Yeah, I'd keep the bass channel.

Take a listen to anything from Social Distortion and Mike's tones are all Bassmans, either blondes or blackfaces, but using the bass channel that's been modified slightly (more for voicing rather than gain).

Hm. Okay. I dig those tones you speak of....but the thing is, I only have 5 holes in the front panel, so my pot selection is going to be a bit, well, limited. I have all sorts of room on the chassis for preamp sockets, but it's the front panel that's severely limiting my options.

I'll have to think on that one...